Analysis of structural and optical properties as well as band alignment of ZnO/TiO ₂ nanocomposite for PEC efficiency improvement

Abstract This study focuses on comparing pure titanium dioxide and its composite with zinc oxide to introduce a cost-effective, high-performance material for photoelectric applications. The desired nanomaterials, synthesized via the sol–gel method, were fabricated as thin layers using the inexpensive spin-coating technique. X-ray diffraction analysis and SEM micrographs confirmed the successful synthesis of spherical titanium dioxide nanostructures, which enhance light absorption. Furthermore, XPS investigations revealed that the formation of type-II (staggered) junctions within the composite effectively improves charge separation and photoelectric efficiency, presenting a promising approach for the sustainable production of electrochemical devices and solar cells. Photoluminescence analysis demonstrated a decrease in intensity with the addition of ZnO, indicating reduced electron–hole recombination rates. Additionally, as an application for solar-driven water splitting, increased photocurrent and reduced onset voltage for hydrogen evolution were observed. In conclusion, the composite enhances light absorption and electron–hole separation processes, thereby increasing electron lifetime and overall efficiency.